Building a Turn Signal Flasher Unit

 Last night I built a circuit using a 555 timer chip, a transistor, and a Hitachi connector that should be a drop-in replacement for the flasher relay on my 1989 Honda Pacific Coast.  While working to convert my bike over to full LED bulbs, I damaged the OEM flasher unit and the self-canceling turn signal controller.  None of the electronic flashers I was able to source locally would work as a drop-in replacement because they still require a higher load than the LED bulbs in the turn signal system on the bike would provide.  Thus I did a quick search on the internet and found this Intructable for building a replacement flasher.  After a quick trip to the Digi-Key website, I had the electronics ordered.  For the Hitachi connector I used Electrical Connection.  Be sure to buy the crimping tool when you buy the connectors.  It is well worth the money.

The end result works as expected on my workbench.  When the rains finally let up here and I can uncover my motorcycles without fear of being drowned, I will test the circuit out on the PC800.  The next step in the project is to get a few diodes and a relay, and bypass the self-cancel control unit that I burned out.  A future iteration of the project will replace that control unit with a home-brewed control module that I am working on with my buddy Brent.

This is the scratch paper I used to make sure I was laying out my circuits correctly and to verify pinouts of various components.  Be sure to check all of the data sheets yourself before trusting my scribbles.  Be extra sure to verify the pinout on the Hitachi connector before you plug this into your motorcycle.  I’m not responsible for any damages that may result if you try this at home!

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  1. rick’s avatar

    no way man i wish i had your talnts its going to cost me $350 to get one of those control units for my 79 GS 1000 L suzuki ride long and happy

    Reply

    1. DouglasVB’s avatar

      Hey Rick,

      It’s not that hard to build your own. If I can do it, anyone can! What part number for your GS 1000L are you trying to replace? I bet there’s an alternative that we can figure out which won’t cost more than $30.

      Cheers!

      Douglas

      Reply

    2. Justin’s avatar

      The part number for the control unit he is referring to is 38830-49000 it was replaced by 38830-49001. I am also in need of a replacement, but it is $350-$450 for the replacement.

      Reply

      1. DouglasVB’s avatar

        Hmm…

        Is there a wiring diagram you can point me toward online for the bike? I might be able to figure something out for your control unit. I just bypassed the self-cancel turn signal module on my Pacific Coast with two relays and a couple of diodes. New price of that unit is $100-200. I paid $10 for components to make it no longer necessary.

        I should note that I found a stock automotive flasher that I was able to drop into my Pacific Coast’s wiring harness. It works great and isn’t as difficult to install/build. Info is here: http://www.douglasvanbossuyt.com/2012/03/26/flasher-replacement-for-the-pc800-that-can-be-used-with-leds/ and here: http://www.douglasvanbossuyt.com/2012/04/16/pc800-full-led-conversion/

        Cheers!

        Douglas

        Reply

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